Im a novice with multimeters. Can you explain how I should test it with one please oh please??? Thanks Don

Set to OHMS. Place red lead on one side black lead on other, look at meter; then reverse leads. OL means blocked, any number means continuity (0.00 is a number). Diode is bad if you read continuity in both directions.
Pretty rare the diode is the problem. More likely the engine coolant t-stat is stuck open, if your problem is no AC and digital temp displays ---. Replace it with ACDelco 131-158 ONLY.

Thanks Donbrew -
I was hoping the diode was bad but it tested fine. Crossing one thing off the list at least. Still cant get the clutch to kick in. I appreciate the help sir.

What about the t-stat?